Soil-inhabiting insects cause damage to certain crops resulting in estimated losses of many millions of dollars each year. For example, wireworms and southern corn rootworms have been estimated to cause losses of 46 million dollars per year and 11 million dollars per year, respectively, in the Southeast alone (ESA Southeastern Branch, Insect Detection, Evaluation and Prediction Report, 1981). Present techniques for controlling these pests rely almost exclusively on soil insecticides which are very expensive (costing as much as 15 to 20 dollars per acre) and have the potential of having adverse ecological and environmental effects.
Certain plants have evolved rather potent chemical defenses which deter feeding by certain insects and it has been suggested previously that such natural feeding deterrents might be used in crop pest management. However, the results from previous attempts to use such deterrents for the control of insects have been poor. Reasons given for this lack of success include phytotoxicity, lack of persistence, socio-economic constraints, and the inability to duplicate laboratory results in the field. Such unsuccessful attempts to use natural feeding deterrents have resulted in the promulgation of suggested sets of criteria that potential feeding deterrents must meet to receive serious consideration for use in the field. Among these criteria are: adequate persistence for crop protection, systemic activity, low cost, and lack of phytotoxicity. While these suggested sets of criteria may have increased the efficiency of screening for effective deterrents, they have not resulted, to our knowledge, in any current commercial use of natural deterrent compounds in the field for crop pest management.
We believe the main reason for the lack of success in the use of natural feeding deterrents for crop pest management is that such prior attempts have focused mainly on the protection of plant foliage and fruit. These attempts at protecting plant foliage and fruit may have been unsuccessful because (1) persistence is needed for extremely long periods of time (2) a high degree of systemic action is needed, and (3) large quantities of the deterrent are needed to treat the foliage and fruit.
With the foregoing in mind, it is an object of the present invention to provide effective crop pest management using natural feeding deterrents which has the required persistence and low cost and in which the need for systemic action is decreased.
A more particular object of the present invention is to provide effective crop pest management by protecting seeds and the below-ground portions of seedlings from damage from certain soil-inhabiting insect pests through the use of plant extracts which are effective feeding deterrents against those soil-inhabiting insect pests which would otherwise damage the seeds or seedlings.